Shin put away his trademark nasty for once:

I simply did not come in expecting anything quite this amazing [..] magnificent portrayal and interpretation of character relationships

He's also lionizing P-san as "guardian angel" and catches hints of continuations. Now I'm hoping he's right.

Suguru wishes for more dorama:

I think if they'd gone the Miki-Haruka smackdown for the Producer route and made better use of the drama from Producer-san's accident, it'd be at an even higher level - but as is it was still fun to watch and I'm sure I'll be rewatching Chihaya and Haruka's arcs, at least, pretty soon.

IMHO they went much further than was generally expected. DiGi in particular was outspoken in that no hint of romance would be allowed or else, if I remember right.

Peter S. admits to certain qualities:

And so, hats off to the creators of iDOLM@STER. It’s hardly a compliment to say this show wasn’t nearly as bad as it could have been, but when you consider that the very concept of an iDOLM@STER anime series would make money, it would have been tempting to just mail it in and watch the bank account grow. But the creators obviously cared about this show. The girls were mostly clichés but they were almost always used to good effect, and they wound up showing more depth than I expected. Their character designs were expressive and fun to look at. And there were so many of them that you’d never get bored of one.

I generally didn't even want to watch the series, just thought compelled as a fan in general.

UPDATE: Bluemist arrives from a perspective of experienced fan:

But for a long-standing fan of the iDOLM@STER games, anime, music, or any other fan-related aspect of it, this anime is legendary. It caters to fans in a very special way, sometimes too much. The producers are well-aware of the fandom outside of the games, and they incorporate some of those references back to the anime. I’m not too keen on those stuff, but I know of various Haruka memes and jokes about Chihaya.

Legendary already? I don't think that world means what he implies. Exhilarating or precious, perhaps. But yes.

UPDATE 2012/01/06: Evirus minces no words:

Leading the way by a large margin in autumn 2011 is The IDOLM@STER TV. I am solidly in the camp that believes Idolmaster exceeded all expectations. It doesn't quite win the coveted No Bad Episodes award (thanks for dragging down the curve, Hibiki), and some of the early summer 2011 episodes stumbled in parts, but taken as a whole Idolm@ster performed very well. As much as I enjoyed Hanasaku Iroha in the spring and summer, iM@S is easily my choice for show of the year. Some may argue Mahou Shoujo Madoka Magica deserves Show of the Year, but I believe its baggage will prevent it from being as fondly remembered in the long run.

I sooo hope he's right about that.